Wire guide module, and ultrasonic wire bonder therewith

ABSTRACT

A wire guide module for an ultrasonic wire bonder, comprising a body made of a thermally stable metallic and/or ceramic material, wherein an elongated wire feed-through channel having a wire inlet opening and having a wire outlet opening is provided on the body, and comprising a guide tube provided in the wire feed-through channel. In addition, the invention relates to a thermosonic wire bonder having a wire guide module.

This nonprovisional application is a continuation of InternationalApplication No. PCT/DE2021/100534, which was filed on Jun. 23, 2021, andwhich claims priority to German Patent Application No. 10 2020 117641.4, which was filed in Germany on Jul. 3, 2020, and which are bothherein incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a wire guide module for an ultrasonicwire bonder. Such wire guide modules are used in wire bonders to guide abond wire through a movable bonding head of the wire bonder to a bondingtool, and to position the wire under the bonding tool of the wire bonderfor the purpose of producing an electrically conductive bond connection.In addition, the invention relates to an ultrasonic wire bonder having awire guide module.

Description of the Background Art

Conventional wire guide modules for wire bonders in use today arechiefly made of plastic, in particular of polyoxymethylene (POM), onaccount of the comparatively low costs and good sliding behavior. Thewire guide modules serve to redirect the wire, which usually is fedvertically from above, and to guide it under the bonding tool. Wireguide modules made of POM are designed as a single piece, and usuallyare produced through primary forming. They melt at approximately 175° C.and are suitable for continuous operation only to just barely above 100°C.

Particularly in thermosonic wire bonders, in which the bonding tooland/or the bond wire and/or the substrate are preheated, for example inorder to be able to bond copper wires or to reduce the process timesduring bonding, the wire guide module also heats up as a result of thethermal energy supplied. Temperatures in the range from 175° C. to 425°C. can be reached at a hottest point of the wire guide module.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to improve a wire guidemodule with respect to its temperature resistance.

Accordingly, in an exemplary embodiment, the wire guide module comprisesa body made of a thermally stable metallic and/or ceramic material,wherein an elongated wire feed-through channel having a wire inletopening and having a wire outlet opening is provided on the body; aguide tube provided in the wire feed-through channel; and a mount forinterlocking positioning of the wire guide module on an attachmentelement of a bonding head of the ultrasonic wire bonder.

The particular advantage of the invention is in that the body producedfrom the temperature-stable metallic or ceramic material can even beused at temperatures of up to 425° C. Impermissibly high heating cannotbe ascertained. The guide tube that is provided in the wire feed-throughchannel and through which the bond wire is guided during bondingprotects the body of the wire guide module according to the inventionfrom mechanical damage by the likewise metallic wire in this design. Theguide tube is designed in this respect as a wearing part and is muchlower in cost than the body. At the same time, friction is reduced bythe provision of the guide tube that the bond wire can be guided andredirected through the wire guide module with little resistance.

The body of the wire guide module according to the invention can beproduced from a cast aluminum alloy or a cobalt chromium tungsten alloy,for example. Good temperature resistance is produced here in each case.For example, a body can be produced from the cobalt chromium tungstenalloy by an additive manufacturing process, which is to say in 3Dprinting. For example, provision can be made that the body is producedfrom aluminum oxide.

The guide tube of the wire guide module according to the invention canbe produced from polytetrafluoroethylene (PTFE), for example, or fromanother temperature-stable plastic with a melting temperature of morethan 175° C. and preferably more than 240° C. and especially preferablymore than 280° C. For example, the guide tube can be made of silicone.

The wire guide module or the body can provide, for example, two oppositeflat side surfaces that are essentially parallel to one another, and acircumferential connecting surface that connects the flat side surfaces.The wire inlet opening and/or the wire outlet opening can be formed onthe connecting surface.

The wire inlet opening can be provided as part of the mount orimmediately adjacent to the mount. The wire outlet opening can beprovided at a distance from the mount.

The wire guide module or the body can be wedge-shaped in design withrespect to the flat side surfaces and/or the connecting surface and/orcan taper toward the wire outlet surface. In this way, it is possible toarrange the wire outlet opening in close proximity to a tip of thebonding tool and to feed the bond wire directly under the bonding tool.

The guide tube can be provided such that it has clearance in the wirefeed-through channel. The installation or replacement of the guide tubeis advantageously simplified by this means. In addition, a gap betweenthe body and the guide tube ensures that the guide tube is heated lessstrongly than the body. Alternatively, the guide tube can be matchedwith respect to its outer diameter to the inner diameter of the wirefeed-through channel such that the guide tube is provided such that ithas essentially no clearance in the wire feed-through channel.

The wire feed-through channel can taper toward the wire outlet opening.Because the bond wire is fed through the wire inlet opening and pulledtoward the wire outlet opening during bonding, the guide tube is securedby the taper of the wire feed-through channel against displacement inthe direction of the wire outlet opening or an undesirable sliding out.

A pocketlike and/or trough-shaped installation recess, which may extendto the wire feed-through channel, can be provided on the body. Owing tothe provision of the installation recess, the insertion or replacementof the guide tube is facilitated and its correct position in the wirefeed-through channel can be optically inspected by visual examination inan especially simple way.

A clamping part can be provided that is inserted in the installationrecess and is fixed there in such a manner that the clamping part is indirect contact with the guide tube. The clamping part secures the guidetube in this way. In particular, provision can be made that the clampingpart is detachably connected to the body by a fastener. Replacement ofthe guide tube is simplified in this way, since the clamping part can bedetached and removed with the result that changing the guide tube issimplified and the correct position of the guide tube in the wirefeed-through channel can be visually inspected prior to reinsertion ofthe clamping part.

An inert gas channel having an inert gas inlet opening can be providedon the body. In particular the inert gas channel opens into the wirefeed-through channel. Advantageously, an inert gas serving as oxidationprotection, in particular a noble gas or a noble gas/gas mixture, can befed through the inert gas channel.

The feeding of the inert gas can be accomplished in such a manner that,for example, the inert gas is fed through the inert gas channel andflows around the guide tube provided such that it has clearance in thewire feed-through channel. The inert gas then exits from the wirefeed-through channel by the wire outlet opening.

For example, provision can be made that a through hole is provided inthe guide tube on the lateral surface and that the guide tube with thethrough hole is arranged in the wire feed-through channel and associatedwith the inert gas channel in such a manner that the inert gas fedthrough the inert gas channel arrives in the guide tube via the throughopening. The provision of the through hole advantageously suggestsitself especially when the guide tube is provided such that it hasessentially no clearance in the wire feed-through channel.

A longitudinal guide, preferably a dovetail guide, can be provided onthe body. The longitudinal guide serves to install the body of the wireguide module according to the invention on an attachmentelement—provided with a correspondingly shaped mount—of a bonding headof the wire bonder. Advantageously, replacement of the body can beaccomplished very easily due to the provision of the longitudinal guide.Furthermore, replacement of the bonding tool is also simplified when thebody is displaceably held on the bonding head by the longitudinal guide.

The temperature-resistant wire guide module can be provided, for examplereplaceably, on a translationally movable and rotatable bonding head ofan ultrasonic wire bonder according to claim 15, which has a thermalgenerator for heating the bonding tool and/or the bond wire and/or asubstrate, and has an ultrasonic transducer for exciting ultrasonicvibrations in the bonding tool. Such ultrasonic wire bonders are alsoreferred to as thermosonic wire bonders. An electrically operatedheating cartridge, a substrate heater, or a laser generator can beprovided as thermal generator, for example.

Additional advantages, features, and details of the invention areevident from the additional dependent claims and the description below.Features mentioned therein can each be essential to the inventionindividually or in any desired combination. Of course, features anddetails of the wire guide module described according to the inventionalso apply in connection with the ultrasonic wire bonder according tothe invention and vice versa. Thus, mutual reference can always be madeto the disclosure of the individual aspects of the invention. Thedrawings serve merely to clarify the invention by way of example, andare not restrictive in nature.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes, combinations,and modifications within the spirit and scope of the invention willbecome apparent to those skilled in the art from this detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are not limitiveof the present invention, and wherein:

FIG. 1 is a flat side view of a wire guide module according to theinvention in an example,

FIG. 2 is a sectional representation of the wire guide module from FIG.1 ,

FIG. 3 is the wire guide module from FIGS. 1 and 2 with a bond wireguided therein,

FIG. 4 is a front face view of the wire guide module from FIGS. 1 to 3 ,

FIG. 5 is an example of the wire guide module according to the inventionin a flat side view,

FIG. 6 is an example of the wire guide module according to the inventionin a flat side view,

FIG. 7 is the wire guide module from FIG. 6 in a sectionalrepresentation,

FIG. 8 is the wire guide module from FIGS. 6 and 7 with the bond wireguided therein,

FIG. 9 is an example of the wire guide module according to the inventionin a flat side view,

FIG. 10 is the wire guide module from FIG. 9 in a sectionalrepresentation,

FIG. 11 is the wire guide module from FIGS. 9 and 10 with the bond wireguided therein,

FIG. 12 is a front face view of the wire guide module from FIGS. 9 to 11,

FIG. 13 is an example of the wire guide module according to theinvention in a flat side view,

FIG. 14 is the wire guide module from FIG. 13 in a sectionalrepresentation,

FIG. 15 is the wire guide module from FIGS. 13 and 14 with the bond wireguided therein,

FIG. 16 is an example of the wire guide module according to theinvention in a perspective, exploded view,

FIG. 17 is a perspective view of a body of the wire guide module fromFIG. 16 ,

FIG. 18 is a flat side view of the body from FIG. 17 with a guide tubeprovided therein,

FIG. 19 is a flat side view of a clamping part of the wire guide modulefrom FIG. 16 , and

FIG. 20 is a flat side view of the wire guide module from FIG. 16 with abond wire guided therein.

DETAILED DESCRIPTION

A first embodiment of a wire guide module according to the inventionfrom FIGS. 1 to 4 provides a body 1, which is produced from a thermallystable metallic or ceramic material, for example from a cast aluminumalloy, a cobalt chromium tungsten alloy, or from aluminum oxide. Thebody 1 has two opposite flat side surfaces 7, 8, and a circumferentialconnecting surface 9 that connects the two flat side surfaces 7, 8.

Provided on the body 1 is a wire feed-through channel 2 for a bond wire11. The wire feed-through channel 2 provides a wire inlet opening 3located in the region of the connecting surface 9 as well as a wireoutlet opening 4. A groove-shaped outlet contour 6, which the wirefeed-through channel 2 opens into and which adjoins the wire outletopening 4, is additionally provided as part of the connecting surface 9.

Provided in the wire feed-through channel 2 is a guide tube 5. The guidetube 5 is made of a plastic with a melting temperature of more than 175°C. and preferably more than 240° C. and especially preferably more than280° C. In the present case, the guide tube 5 is made of PTFE. The guidetube 5 is provided such that it has essentially no clearance in the wirefeed-through channel 2.

In order to guide the bond wire 11 to a bonding tool and position itunder a tip of the bonding tool, the bond wire 11, which, in particular,is fed vertically through the wire inlet opening 3, is redirected in thewire feed-through channel 2 toward the bonding tool. The bond wire 11leaves the wire feed-through channel 2 through the wire outlet opening4, which is arranged at an incline to the bonding tool and arrives inthe groove-shaped outlet contour 6 of the wire guide module, whichcontour is open toward the bonding tool.

For the purpose of installing the wire guide module according to theinvention on a bonding head of the wire bonder, the wire guide moduleprovides a longitudinal guide, in the present case a dovetailedlongitudinal guide, as a mount 10. The longitudinal guide 10 is providedon the body 1 of the wire guide module 1. It extends in the region ofthe opposing flat side surfaces 7, 8 and, at the same time, surroundsthe wire inlet opening 3 of the wire feed-through channel 2.

FIG. 5 shows a second embodiment of the invention with a body 1 thatprovides an installation recess 12 on the first flat side surface 7,which recess is routed to the wire feed-through channel 2. Theinstallation recess 12 is provided in order to simplify the installationof the guide tube 5 in the wire feed-through channel 2, on the one hand.On the other hand, a correct positioning of the guide tube 5 in the wirefeed-through channel 2 can be visually inspected by visual examination.The guide tube 5 in this case is preferably provided such that it hasessentially no clearance in the wire feed-through channel 2. Theinstallation recess 12 can be formed as a through recess or bepocketlike or trough-shaped.

According to a third embodiment of the invention from FIGS. 6 to 8 , theinstallation recess 12, which extends to the wire feed-through channel2, is formed on the body 1 of the wire guide module according to theinvention in the region of the first flat side surface 7. A clampingpart 13 is inserted in the installation recess 12, which is pocketlikeor trough-shaped in the present case. The clamping part 13 is fixed inposition by a screw 14, which engages in a screw receptacle 15 formed onthe body 1. In the installed state of the wire guide module, theclamping part 13 serves to secure, fix, or position the guide tube 5that is provided such that it has clearance in the wire feed-throughchannel 2. At the same time, the clamping part 13 can be removed.Removal or installation of the guide tube 5 is simplified by this means,since exact positioning of the guide tube 5 in the wire feed-throughchannel 2 of the body 1 can be visually inspected on account of theinstallation recess 12 formed on the body 1. The installation recess 12has a dual function in this respect. It serves on the one hand tosimplify installation and removal of the guide tube 5, and on the otherhand to accommodate the clamping part 13 that is provided for securingthe guide tube 5.

FIGS. 9 to 12 show a fourth embodiment of the wire guide moduleaccording to the invention. In this design, an inert gas channel 16,which provides an inert gas inlet opening 17 and is routed to the wirefeed-through channel 2, is formed on the body 1 in addition to the wirefeed-through channel 2 and the installation recess 12. The inert gasinlet opening 17 is part of a connector 18 that is provided on theconnecting surface 9 and serves to connect an inert gas line. A gas thatserves the purpose of oxidation protection, in particular a noble gas ora noble gas mixture, can be fed through the inert gas channel 16. In thepresent exemplary embodiment of the invention, the guide tube 5 isprovided such that it has clearance in the wire feed-through channel 2.The inert gas fed through the inert gas channel 16 arrives in the wirefeed-through channel 2 and flows around the guide tube 5 on the lateralsurface. Some of the inert gas preferentially exits through the wireoutlet opening 4 and inhibits the reaction of the bond wire 11 and/or ofthe substrate (weld joint partners) with the environment or with theoxygen in the ambient air during processing of the bond wire 11, whichis to say during production of the friction-welded connection.

The preferred exit of the inert gas through the wire outlet opening 4 isaccomplished by the means that the inert gas channel 16 is routed to thewire feed-through channel 2 at an acute angle, and the inert gaspreferentially flows toward the wire outlet opening 4 due to theinclination of the inert gas channel 16 in the region of the opening.

In a fifth embodiment of the invention from FIGS. 13 to 15 , the wireguide module also provides an inert gas channel 16. At the same time,the guide tube 5 is held with essentially no clearance in the wirefeed-through channel 2. In order to cause the inert gas fed through theinert gas channel 16 to exit through the wire outlet opening 4, athrough opening 19 is provided in the guide tube 5 on the lateralsurface. The guide tube 5 with the through opening 19 is now arranged inthe wire feed-through channel 2 and associated with the inert gaschannel 16 in such a manner that the inert gas fed through the inert gaschannel 16 arrives in the guide tube 5 through the through opening 19and can escape via the wire outlet opening 4.

According to a sixth embodiment of the invention from FIGS. 16 to 20 ,the wire guide module provides the body 1 having the wire feed-throughchannel 2 formed therein and the clamping part 13, which is inserted inthe installation recess 12 formed on the body 1. In the sixth exemplaryembodiment of the invention, the installation recess 12 is implementedin such a manner that it extends from the first flat side surface 7 tothe connecting surface 9. In this respect, the installation recess 12allows still further simplified removal or installation of the guidetube 5. Otherwise, the clamping part 13 is fixed to the body 1 of thewire guide module by the screw 14 as before.

The new structural or functional features of the respective wire guidemodule are discussed in each of the exemplary embodiments two throughsix of the invention, whereas functional or structural features of apreceding embodiment of the invention that have already been describedand incorporated are not discussed again. Identical components andcomponent functions are labeled with identical reference symbols here.

The invention is not limited to the exemplary embodiments shown. Forexample, provision can be made that the installation recess is providedsolely in the region of the connecting surface and/or extends in adirection in which the wire feed-through channel extends.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are to beincluded within the scope of the following claims.

What is claimed is:
 1. A wire guide module for an ultrasonic wirebonder, the wire guide module comprising: a body made of a thermallystable metallic and/or ceramic material; an elongated wire feed-throughchannel having a wire inlet opening and having a wire outlet opening isprovided on the body; and a guide tube arranged in the wire feed-throughchannel.
 2. The wire guide module according to claim 1, wherein the bodyprovides a cast aluminum alloy or a cobalt chromium tungsten alloy asthermally stable material, and/or wherein the body is produced fromaluminum oxide.
 3. The wire guide module according to claim 1, whereinthe guide tube is flexible, and/or wherein the guide tube is producedfrom a plastic with a melting temperature of more than 175° C., or morethan 240° C. or more than 280° C., and/or wherein the guide tube isproduced from PTFE.
 4. The wire guide module according to claim 1,wherein a pocketlike and/or trough-shaped installation recess isprovided on the body, and wherein the installation recess is routed tothe wire feed-through channel.
 5. The wire guide module according toclaim 4, wherein a clamping part is provided that is inserted in theinstallation recess and is fixed in the installation recess, wherein theclamping part is in direct contact with the guide tube in order tosecure and/or fix and/or position the guide tube in the wirefeed-through channel.
 6. The wire guide module according to claim 1,wherein the guide tube is provided such that it has a clearance in thewire feed-through channel.
 7. The wire guide module according to claim1, wherein the wire feed-through channel tapers toward the wire outletopening.
 8. The wire guide module according to claim 1, wherein an inertgas channel having an inert gas inlet opening is provided on the bodyfor feeding an inert gas.
 9. The wire guide module according to claim 8,wherein the inert gas channel opens into the wire feed-through channeland/or wherein the inert gas channel is routed to the wire feed-throughchannel at an acute angle such that the inert gas flows toward the wireoutlet opening due to the inclination of the inert gas channel in theregion of an opening.
 10. The wire guide module according to claim 8,wherein the guide tube provides a through opening on a lateral surface,and wherein the guide tube with the through opening is arranged in thewire feed-through channel and associated with the inert gas channel suchthat the inert gas fed through the inert gas channel arrives in theguide tube through the through opening.
 11. The wire guide moduleaccording to claim 8, wherein a mount is provided for interlockingpositioning of the wire guide module on an attachment element of abonding head of the ultrasonic wire bonder and/or wherein a longitudinalguide is provided on the body as the mount for installing the body on acorrespondingly shaped attachment element of a bonding head of the wirebonder, the longitudinal guide being formed as a dovetail guide.
 12. Thewire guide module according to claim 1, wherein the wire inlet openingis provided in a region of the mount and/or is surrounded thereby and/orin wherein the wire outlet opening is opposite a mount.
 13. The wireguide module according to claim 1, wherein the body provides a firstflat side surface and a second flat side surface opposite the first flatside surface, as well as a circumferential connecting surface thatconnects the first flat side surface to the second flat side surface,wherein the installation recess is formed on the first flat side surfaceor in a region of the first flat side surface and the connectingsurface, and/or wherein the wire inlet opening and/or the wire outletopening and/or the inert gas inlet opening are provided in theconnecting surface.
 14. The wire guide module according to claim 13,wherein a groove-shaped outlet contour, which the wire feed-throughchannel opens into and/or which adjoins the wire outlet opening, isformed as part of the connecting surface.
 15. An ultrasonic wire bondercomprising: a linearly and/or rotationally movable bonding head, whereina bonding tool that is adapted to be excited into ultrasonic vibrationsvia an ultrasonic transducer is replaceably held on the bonding head; athermal generator for heating the bonding tool and/or the bond wireand/or a substrate; and the wire guide module according to claim1,wherein the wire guide module is formed as part of the bonding head forfeeding a bond wire to the bonding tool.